The present invention relates generally to dual circuit hydraulic braking systems for automotive vehicles and, more particularly to tandem master cylinders incorporated in such braking systems.
Conventional dual circuit braking systems are provided with tandem master cylinders which are hydraulically connected to the dual circuits of the braking systems for therethrough applying the brakes on front and rear sets of vehicle wheels.
Such braking systems encounter a drawback that the failure of one circuit leads to losses in pedal stroke, in other words, an increase in pedal movement before braking effect is obtained and further encounter a drawback that the braking effect obtained by the braking system with one broken-down circuit is reduced to half by the intact system for the same pedal force.
This deterioration in braking performance can give the driver a shock and will create a panic situation.
It is known in the art that tandem master cylinders cause such drawbacks of the braking system with one broken-down circuit.
To overcome the above drawbacks, various tandem master cylinders have therefore been proposed but ended in failure because the tandem master cylinders having hitherto been proposed still lead to considerable large losses in pedal stroke and still require increased pedal force in the event of failure of the braking system and, further, because the conventional tandem master cylinders have complicated construction and large size, particularly with respect to their axial length, which disadvantageously increases the manufacturing cost.